Practical applications, LED display shows water wave phenomenon has become an important quality high-definition display obstacle, then what produced this phenomenon is why, how should we deal with?
First, the difference between the water ripples and the scanning lines phenomenon
1, the water ripples: general state presented no arc diffusion rules!
2, the scanning lines: horizontal black stripe straight, mainly due to the lower screen refresh is captured by the camera show!
Second, the "water ripple" generic "moire"
The scene with a digital camera, if there is the compact texture, often inexplicable wave-like stripes. This is the moire. Simply put, moiré is a manifestation of the principle of the beat. Mathematically speaking, the two frequencies close amplitude sine-wave superimposed, the amplitude of the combined signal will vary according to the difference between the two frequencies.
Third, the process produced moiré
1, the two spatial frequency slightly different stripe, they left the same black line position, due to the different intervals, gradually to the right of the streaks will not overlap.
2, two streaks overlap, since the coincidence left black line, it is possible to see the white line. And the right to gradually dislocation, white lines against a black line, overlapping the results become all black. There are white lines and all black changes in the composition of moiré.
Four, LED display moiré phenomenon procedure
LED display pixel density among the CCD can tell exactly between intervals, inevitably digital camera or will interpret section discernible results, but will also add unrecognized gray zone, and on both will form regular patterns, visual sensation is periodically corrugated.
Fifth, eliminate moiré method
1, change camera angles. Since the camera angle of the object can cause moiré, slightly changing the angle of the camera, by rotating the camera, you can eliminate or change any moiré exist.
2, change the camera position. In addition to changing the angle relationship by moving left and right or up and down, you can reduce moiré.
3, change the focus. Too sharp focus and high detail may cause moiré, slightly changing the focus can change the resolution, thus helping to eliminate moiré.
4, change the lens focal length. Available Ji with lenses or focal length settings to change or eliminate moiré.
5, before using mirror filters installed directly in front of the CCD, making spatial frequency exposure conditions, completely filtered images with high spatial frequency components, reducing the chance of occurrence of moiré, but also reduce the sharpness of the image synchronization.